Update citations of Internet RFCs

For example, RFC 822 has been obsoleted by RFC 2822, which in
turn has been obsoleted by RFC 5322.
* doc/emacs/ack.texi, doc/lispref/os.texi:
* doc/misc/emacs-mime.texi, doc/misc/gnus-coding.texi:
* doc/misc/gnus.texi, doc/misc/sc.texi:
* lisp/calendar/parse-time.el, lisp/gnus/gnus-cite.el:
* lisp/gnus/gnus-util.el, lisp/gnus/message.el:
* lisp/gnus/mm-bodies.el, lisp/gnus/nnrss.el:
* lisp/mail/feedmail.el, lisp/mail/ietf-drums.el:
* lisp/mail/mail-extr.el, lisp/mail/mail-utils.el:
* lisp/mail/mailclient.el, lisp/mail/mailheader.el:
* lisp/mail/rfc2047.el, lisp/mail/rfc822.el, lisp/mail/rmail.el:
* lisp/mail/sendmail.el, lisp/mail/smtpmail.el:
* lisp/mail/supercite.el, lisp/mh-e/mh-e.el:
* lisp/mh-e/mh-utils.el, lisp/net/imap.el:
* lisp/net/newst-backend.el, lisp/org/org-id.el:
* lisp/ps-samp.el, lisp/simple.el, lisp/url/url-util.el:
Update RFC citations.

1 files changed, 1 insertions, 1 deletions

diff --git a/doc/lispref/os.texi b/doc/lispref/os.texi
index 2f3e91ce68c..a04f03bd463 100644
--- a/doc/lispref/os.texi
+++ b/doc/lispref/os.texi
@@ -1485,7 +1485,7 @@ following form:
 The format of this list is the same as what @code{decode-time} accepts
 (@pxref{Time Conversion}), and is described in more detail there.  Any
 element that cannot be determined from the input will be set to
-@code{nil}.  The argument @var{string} should resemble an RFC 2822 or
+@code{nil}.  The argument @var{string} should resemble an RFC 822 (or later) or
 ISO 8601 string, like ``Fri, 25 Mar 2016 16:24:56 +0100'' or
 ``1998-09-12T12:21:54-0200'', but this function will attempt to parse
 less well-formed time strings as well.